po 171

[dnmir54]

THE FOLLOWING IS FROM A 1996 S10 4.3 WITH 196,000 miles replaced cap and rotor and spark plugs so far

bought a code scanner after cleaning the mass air flow sensor
pulled po171 lean bank, the other two codes that were pulled at the emission test station did not show up po174 and po719

erased the code and drove vehicle 1-2 miles parked and drove it again the po171 code comes up again

here is what the freeze frame gave me from code scanner
fuelsystem 1 cl
fuel system2 cl
calc load % 2.75
ect(%) 92
stft B1 % 3.91
ltft B1 % 25.00
stft B2 % 3/13
ltft B2 % 25.00
map ( k Pa) 35.00
eng rpm 955
vch speed 50 mph
maf (g /s) 5.83

can anyone TRANSLATE OR MAKE SENSE OF THIS FOR ME

[danielsatur]

Check for unmeter air leaks on PCV, EGR, and Air Intake systems.

Because of the Age + mileage, suspect bad plastic, rubber, seals, or gaskets.

[MT-2500]

710 is a brake switch circuirt problem.
Just watch for code to return on that one.

171-174 is left and right bank lean /engine running lean as shown in LT fuel trim readings.

As said check for air leaks.

Low fuel pressure can give engine running lean problems and codes.

Any other engine running running or starting problems?

The only true test on a fuel pump is to check the direct fuel pressure from fuel pump.
A quick test is to block off the return line and see if fuel pressure comes up to 75-85 lbs.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold or hot and fuel pressure testing guide lines.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak in system.
Post back fuel pressure readings.